Tighter security measures could be brought in at a mental health unit in Sheffield after the death of a patient who escaped.

Widow Pamela Bailey disappeared from the Hawthorn ward of the Northern General Hospital in Sheffield last March after she mastered the key codes staff used to open doors.

The keen walker’s freezing cold body was found in the snow six days later at Ladybower Brook in Derbyshire.

An inquest into the 68-year-old’s death heard the ward was short-staffed the night she walked out.

Mrs Bailey, of Millhouses, had gone missing a day earlier while on overnight leave from the ward.

She had been found walking up a dual carriageway in Derby.

Staff nurse Hilary Leigh said: “There are usually four of us but on the Saturday shift it was me and two support workers. I remember seeing Pamela that night relaxed and reading.”

Dr Claire Littlewood, consultant in old age psychology at the Hawthorn ward, told the hearing at the Medico Legal Centre staff were aware Mrs Bailey knew door key codes.

She had been admitted in September 2012 suffering with depression brought on by her husband Neil’s illness.

She said: “She was clearly a very intelligent woman. Had we changed codes I am sure it would not have taken her long to learn them, delaying rather than preventing it. There has been discussion about using a swipe system on top of existing codes.”